Method and apparatus for outer-loop power control for enhanced uplink communications

Abstract

Various embodiments are described to address the need for an apparatus and method of outer-loop power control for enhanced uplink communications that address some of the outstanding problems in the prior art. Generally expressed, a base site ( 131 ), while a first uplink channel is inactive, monitors packet retransmissions to generate an uplink quality indicator. Here, packet retransmissions refers to the number of packet retransmissions used by a remote unit ( 101 ) to send packets to a base transceiver station ( 111 ) via at least one other uplink channel. Also, while the first uplink channel is inactive, the base site adjusts a signal-to-interference ratio (SIR) target for the first uplink channel based on the uplink quality indicator. Then, when the first uplink channel becomes active, the base site begins power controlling the first uplink channel using the SIR target.

1 . A method for outer-loop power control for enhanced uplink communications comprising: 
 while a first uplink channel is inactive, monitoring a number of packet retransmissions to generate an uplink quality indicator, wherein the number of packet retransmissions is the number of packet retransmissions used by a remote unit to send packets to a base transceiver station (BTS) via at least one other uplink channel;    while the first uplink channel is inactive, adjusting a signal-to-interference ratio (SIR) target for the first uplink channel based on the uplink quality indicator; and    when the first uplink channel becomes active, power controlling the first uplink channel using the SIR target.    
   
   
       2 . The method of  1 , wherein power controlling the first uplink channel using the SIR target comprises power controlling the first uplink channel using the SIR target and a SIR target for the at least one other uplink channel.  
   
   
       3 . The method of  2 , 
 wherein the first uplink channel comprises an enhanced data channel (E-DCH),    wherein the at least one other uplink channel comprises a data channel (DCH),    wherein power controlling the first uplink channel comprises adjusting a power offset factor between the E-DCH and associated DPCCH to change the power of the E-DCH, and    wherein the SIR target and the SIR target for the DCH are used to adjust the power offset of the E-DCH and the DCH.    
   
   
       4 . The method of  1 , 
 wherein the first uplink channel comprises an enhanced data channel (E-DCH) that is a transport channel carried on the Enhanced-Dedicated Physical Data Channel (E-DPDCH),    wherein the at least one other uplink channel comprises a data channel (DCH) that is a transport channel carried on the Dedicated Physical Data Channel (DPDCH), and    wherein the BTS comprises a Node B.    
   
   
       5 . The method of  4 , wherein separate outer loops are used to power control the E-DCH and DCH.  
   
   
       6 . The method of  1 , 
 wherein monitoring the number of packet retransmissions to generate an uplink quality indicator comprises generating the uplink quality indicator based on an average number of packet retransmissions over a period of time.    
   
   
       7 . The method of  6 , 
 wherein monitoring the number of packet retransmissions to generate an uplink quality indicator comprises generating the uplink quality indicator based on hybrid automatic retransmission request (HARQ) packet retransmissions.    
   
   
       8 . The method of  1 , 
 wherein adjusting the SIR target for the first uplink channel comprises increasing the SIR target when the uplink quality indicator reaches a threshold.    
   
   
       9 . The method of  8 , 
 wherein adjusting the SIR target for the first uplink channel comprises decreasing the SIR target when the uplink quality indicator does not reach the threshold.    
   
   
       10 . The method of  1 , further comprising 
 periodically sending by the BTS the uplink quality indicator to a base controller,    wherein monitoring the number of packet retransmissions comprises monitoring by the BTS the number of packet retransmissions, and    wherein adjusting the SIR target comprises adjusting by the base controller the SIR target.    
   
   
       11 . The method of  1 , further comprising: 
 while the first uplink channel is active, decoding, by the BTS, a packet received from the remote unit via the first uplink channel, wherein the received packet is a first HARQ transmission of the packet; and    when a packet error is detected for the received packet, increasing a SIR target for the first uplink channel.    
   
   
       12 . The method of  11 , further comprising: 
 when a packet error is not detected for the received packet, decreasing SIR target for the first uplink channel.    
   
   
       13 . The method of  11 , further comprising: 
 sending by the BTS an indication to a base controller that the packet error was detected, wherein increasing the SIR target for the first uplink channel comprises increasing the SIR target by the base controller.    
   
   
       14 . The method of  11 , wherein sending by the BTS the indication to the base controller that the packet error was detected comprises sending the indication with the decoded packet.  
   
   
       15 . The method of  11 , wherein sending by the BTS the indication to the base controller that the packet error was detected comprises sending an indication with the decoded packet of how many retransmissions were required for a successful decode.  
   
   
       16 . A base site comprising: 
 a base transceiver station (BTS) adapted to monitor, while a first uplink channel is inactive, a number of packet retransmissions to generate an uplink quality indicator, wherein the number of packet retransmissions is the number of packet retransmissions used by a remote unit to send packets to the BTS via at least one other uplink channel; and    a base controller, communicatively coupled to the BTS, 
 adapted to adjust, while the first uplink channel is inactive, a signal-to-interference ratio (SIR) target for the first uplink channel based on the uplink quality indicator and  
 adapted to instruct the BTS to power control the first uplink channel using the SIR target when the first uplink channel becomes active.  
   
   
   
       17 . The base site of  16 , wherein the BTS comprises a Node B and wherein the base controller comprises a radio network controller (RNC).  
   
   
       18 . The base site of  16 , wherein the BTS is further adapted to power control the first uplink channel using the SIR target and a SIR target for the at least one other uplink channel.  
   
   
       19 . The base site of  18 , 
 wherein the first uplink channel comprises an enhanced data channel (E-DCH),    wherein the at least one other uplink channel comprises a data channel (DCH),    wherein power controlling the first uplink channel comprises adjusting a power offset factor between the E-DCH and associated DPCCH to change the power of the E-DCH, and    wherein the SIR target and the SIR target for the DCH are used to adjust the power offset of the E-DCH and the DCH.    
   
   
       20 . The base site of  16 , 
 wherein the first uplink channel comprises an enhanced data channel (E-DCH) that is a transport channel carried on the Enhanced-Dedicated Physical Data Channel (E-DPDCH),    wherein the at least one other uplink channel comprises a data channel (DCH) that is a transport channel carried on the Dedicated Physical Data Channel (DPDCH), and    wherein the BTS comprises a Node B.